Drug Resistance Of Colorectal Cancer Cells Research Articles

Polyunsaturated Fatty Acids in Quinoa Induce Ferroptosis of Colon Cancer by Suppressing Stemness.

Polyunsaturated fatty acids (PUFAs) are essential nutrients for the human body, playing crucial roles in reducing blood lipids, anti-inflammatory responses, and anticancer effect. Quinoa is a nutritionally sound food source, rich in PUFAs. This study investigates the role of quinoa polyunsaturated fatty acids (QPAs) on quelling drug resistance in colorectal cancer. The results reveal that QPA downregulates the expression of drug-resistant proteins P-gp, MRP1, and BCRP, thereby enhancing the sensitivity of colorectal cancer drug-resistant cells to the chemotherapy drug. QPA also inhibits the stemness of drug-resistant colorectal cancer cells by reducing the expression of the stemness marker CD44. Consequently, it suppresses the downstream protein SLC7A11 and leads to ferroptosis. Additionally, QPA makes the expression of ferritin lower and increases the concentration of free iron ions within cells, leading to ferroptosis. Overall, QPA has the dual-function reversing drug resistance in colorectal cancer by simultaneously inhibiting stemness and inducing ferroptosis. This study provides a new option for chemotherapy sensitizers and establishes a theoretical foundation for the development and utilization of quinoa.

Fe-MOF nanoplatform: Specifically overcoming oxaliplatin resistance in colorectal cancer through multifaceted pathways

Oxaliplatin (OXA) is a widely used chemotherapy drug for advanced colorectal cancer (CRC), yet resistance frequently and rapidly develops in patients. Here, we explored a Fe-based metal-organic framework (Fe-MOF) as a nanoplatform to simultaneously deliver OXA and a nitric oxide (NO) donor, specifically l-Arginine (L-Arg). The aim was to overcome OXA resistance in CRC cells, thereby enhancing the anticancer efficacy against drug-resistant CRC. Due to the abundant glutathione (GSH) in tumor tissue, Fe3+ in Fe-MOF undergoes reduction to Fe2+, causing the collapse of Fe-MOF structure and the subsequent release of OXA and L-Arg. This process is accompanied by GSH depletion, amplifying the effectiveness of OXA against drug-resistant CRC. Fe2+ further reacts with overexpressed H2O2 to generate •OH, inducing direct cell apoptosis and subsequently reacting with L-Arg to rapidly produce NO. NO plays multifaceted roles in the anti-CRC effect, reversing drug resistance in CRC cells through multiple pathways, inducing apoptosis of CRC cells to initiate gas therapy, and reacting with •OH to generate highly toxic reactive nitrogen species for cancer cell destruction. This synergistic strategy effectively addresses the challenge of drug resistance in CRC, offering a promising avenue for enhancing the clinical effectiveness of OXA in cases resistant to conventional treatment.

The potential therapeutic effect of melatonin in oxaliplatin combination therapy against chemoresistant colorectal cancer cells.

Oxaliplatin is one of the main therapeutics in colorectal cancer (CRC) chemotherapy. However, in light of multidrug resistance (MDR) phenotype development, the efficacy of oxaliplatin has decreased. This study aimed to assess the potential therapeutic effect of melatonin in oxaliplatin combination therapy for drug-resistant colorectal cancer cells. Initially, the oxaliplatin-resistant cell line was created of LS174T (LS174T/DR) by using the oxaliplatin IC50 concentration and resting cycles. MTT assays and flow cytometry were applied for assessing cell viability and apoptotic cells. The mRNA expression level of Bax, Bcl2, MT1, MT2, and ABCB1 as well as protein levels of ABCB1, Bcl2, BAX were measured by the qRT-PCR and western blot techniques respectively. P-gp activity was assessed by Rho123 staining. The IC50 concentration of oxaliplatin in resistant cells was increased from 500.7 ± 0.2 nM to 7119 ± 0.1 nM. Bcl2, MT1, MT2, and ABCB1 mRNA plus protein expression levels of Bcl2 and ABCB1 were significantly reduced in resistant cells, along with a marked increase in Bax mRNA and protein levels compared to parental cells. Rho 123 staining revealed a marked reduction in P-gp activities in the combination-treated group compared to the oxaliplatin-treated group. The results of cytotoxicity assays, MTT, and flow cytometry revealed that the combination of melatonin and oxaliplatin exerts synergistic effects on induction of oxaliplatin's cytotoxicity in CRC. Our research suggests that combining the treatments of melatonin and oxaliplatin may be considered as a new approach to overcoming oxaliplatin resistance in CRC patients.

Regenerating gene 4 promotes chemoresistance of colorectal cancer by affecting lipid droplet synthesis and assembly.

Regenerating gene 4 (REG4) has been proved to be carcinogenic in some cancers, but its manifestation and possible carcinogenic mechanisms in colorectal cancer (CRC) have not yet been elucidated. Our previous study found that the drug resistance of CRC cells may be closely linked to their fat metabolism. To explore the role of REG4 in CRC and its association with lipid droplet formation and chemoresistance. We conducted a meta-analysis and bioinformatics and pathological analyses of REG4 expression in CRC. The effects of REG4 on the phenotypes and related protein expression were also investigated in CRC cells. We detected the impacts of REG4 on the chemoresistance and lipid droplet formation in CRC cells. Finally, we analyzed how REG4 regulated the transcription and proteasomal degradation of lipogenic enzymes in CRC cells. Compared to normal mucosa, REG4 mRNA expression was high in CRC (P < 0.05) but protein expression was low. An inverse correlation existed between lymph node and distant metastases, tumor-node-metastasis staging or short overall survival and REG4 mRNA overexpression (P < 0.05), but vice versa for REG4 protein expression. REG4-related genes included: Chemokine activity; taste receptors; protein-DNA and DNA packing complexes; nucleosomes and chromatin; generation of second messenger molecules; programmed cell death signals; epigenetic regulation and DNA methylation; transcription repression and activation by DNA binding; insulin signaling pathway; sugar metabolism and transfer; and neurotransmitter receptors (P < 0.05). REG4 exposure or overexpression promoted proliferation, antiapoptosis, migration, and invasion of DLD-1 cells in an autocrine or paracrine manner by activating the epidermal growth factor receptor-phosphoinositide 3-kinase-Akt-nuclear factor-κB pathway. REG4 was involved in chemoresistance not through de novo lipogenesis, but lipid droplet assembly. REG4 inhibited the transcription of acetyl-CoA carboxylase 1 (ACC1) and ATP-citrate lyase (ACLY) by disassociating the complex formation of anti-acetyl (AC)-acetyl-histone 3-AC-histone 4-inhibitor of growth protein-5-si histone deacetylase;-sterol-regulatory element binding protein 1 in their promoters and induced proteasomal degradation of ACC1 or ACLY. REG4 may be involved in chemoresistance through lipid droplet assembly. REG4 reduces expression of de novo lipid synthesis key enzymes by inhibiting transcription and promoting ubiquitination-mediated proteasomal degradation.

IGF2BP3 promotes the progression of colorectal cancer and mediates cetuximab resistance by stabilizing EGFR mRNA in an m6A-dependent manner

Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), an RNA-binding protein, is associated with tumorigenesis and progression. However, the exact molecular mechanisms of IGF2BP3 in colorectal cancer (CRC) oncogenesis, progression, and drug resistance remain unclear. This study found that IGF2BP3 was upregulated in CRC tissues. Clinically, the elevated IGF2BP3 level is predictive of a poor prognosis. Functionally, IGF2BP3 enhances CRC tumorigenesis and progression both in vitro and in vivo. Mechanistically, IGF2BP3 promotes epidermal growth factor receptor (EGFR) mRNA stability and translation and further activates the EGFR pathway by serving as a reader in an N6-methyladenosine (m6A)-dependent manner by cooperating with METTL14. Furthermore, IGF2BP3 increases the drug resistance of CRC cells to the EGFR-targeted antibody cetuximab. Taken together, our results demonstrated that IGF2BP3 was a functional and clinical oncogene of CRC. Targeting IGF2BP3 and m6A modification may therefore offer rational therapeutic targets for patients with CRC.

Sanguisorba officinalis L. enhances the 5-fluorouracil sensitivity and overcomes chemoresistance in 5-fluorouracil-resistant colorectal cancer cells via Ras/MEK/ERK and PI3K/Akt pathways

Sanguisorba officinalis L., a traditional Chinese medicine (TCM) called DiYu (DY) in China, has a strong tradition of utilization as a scorching, blood-cooling, and hemostatic medication, and was used for cancer prevention and treatment due to its potential immune-enhancing and hematological toxicity-reducing effects. Previous studies have reported significant effects of DY on cancers including colorectal cancer (CRC), which is one of the most common malignancies worldwide. The first-line cure 5-fluorouracil (5-FU) plays decisive commerce in the sedative of CRC as a clinically available chemotherapeutic agent. One of the primary causes of cancer treatment failure is the acquisition of chemotherapy drug resistance. In order to successfully combat the emergence of chemoresistance, it is essential to identify herbs or traditional Chinese medicine that have adjuvant therapeutic effects on CRC. Therefore, this study aimed to determine whether DY could improve the sensitivity, conquer the chemoresistance of 5-FU-resistant CRC cells, and investigate its intrinsic mechanism. Materials and methodsMTT, Hoechst 33258 staining, and flow cytometry assays were used to determine the anticancer activity of DY alone or in combination with 5-FU against 5-FU-resistant CRC cells (RKO-R and HCT15-R) and wound healing assays were conducted to detect cell migration. Transcriptomic techniques were carried out to explore the effect and mechanism of DY on drug-resistant CRC cells. Western Blot and RT q-PCR assays were performed to validate the mechanism by which DY overcomes drug-resistant CRC cells. ResultsThese results indicated that DY alone or in combination with 5-FU significantly inhibited the proliferation and the migration of resistant CRC cells, and potentiated the susceptibility of 5-FU to drug-resistant CRC cells. GO and KEGG enrichment analysis showed that the mechanisms of drug resistance in CRC cells and DY against drug-resistant CRC cells highly overlapped, involved in the modulation of biological processes such as cell migration, positive regulation of protein binding and cytoskeleton, and MAPK (Ras-ERK-MEK), PI3K/Akt, and other signaling pathways. Moreover, DY can mediate the expression of p-R-Ras, p-ERK1/2, p-MEK1/2, p-PI3K, p-AKT, HIF-1A and VEGFA proteins. In addition, DY significantly suppressed the expression of AKT3, NEDD9, BMI-1, and CXCL1 genes in resistant CRC cells. ConclusionIn conclusion, DY could inhibit the proliferation and migration of 5-FU-resistant cells and strengthen the sensitivity of 5-FU to CRC-resistant cells. Furthermore, DY may prevail over chemoresistance through the Ras/MEK/ERK and PI3K/Akt pathways. These findings imply that DY may be a potential drug for clinical treatment or adjuvant treatment of drug-resistant CRC.

TYRO3 promotes tumorigenesis and drug resistance in colorectal cancer by enhancing the epithelial-mesenchymal transition process

Colorectal cancer (CRC) is a leading cause of cancer mortality worldwide. Although considerable advances in CRC treatment have been achieved, effective treatment improvement has hit a bottleneck. This study demonstrated that TYRO3 expression was aberrantly increased in CRC tissues with prognosis association. The prediction model of prognosis for CRC patients was constructed based on TYRO3 expression. The model suggested that the TYRO3 level is crucial to the final prediction results. We observed that knockdown TYRO3 expression could inhibit the proliferation and migration ability and reverse the drug resistance by constructing drug-resistant CRC cell lines. In vivo experiments also confirmed this conclusion. Thus, targeting TYRO3 combined with 5-Fu treatment could provide a better therapeutic effect. Additionally, TYRO3 could inhibit the EMT process by down-regulating ENO1, which may be achieved by interfering with energy metabolism in cancer cells. Therefore, the current study provides a theoretical basis for TYRO3 in drug-resistance of CRC cells and highlights a new strategy for CRC-targeted therapy.

The roles of protocadherin-7 in colorectal cancer cells on cell proliferation and its chemoresistance.

Despite the high mutation frequencies of KRAS, NRAS, and BRAF in colorectal cancer (CRC), there are no effective and reliable inhibitors for these biomarkers. Protocadherin-7 (PCDH7) is regarded as a potentially targetable surface molecule in cancer cells and plays an important role in their proliferation, metastasis, and drug resistance. However, the roles and underlying mechanisms of PCDH7 in CRC remain unclear. In the current study, we found that different colorectal cancer cells expressed PCDH7 over a wide range. The levels of PCDH7 expression were positively associated with cell proliferation and drug resistance in CRC cells but negatively correlated with the potential for cell migration and invasion. Our data indicated that PCDH7 mediated the resistance of CRC cells to ABT-263 (a small-molecule Bcl-2 inhibitor that induces apoptosis) by inhibiting cell apoptosis, which was supported by the downregulation of caspase-3, caspase-9, and PARP cleavage. We found that PCDH7 effectively promoted Mcl-1 expression at both mRNA and protein levels. Furthermore, PCDH7 activated the Wnt signaling pathway, which was confirmed by the increase in β-catenin and c-Myc expression. Finally, and notably, S63845, a novel Mcl-1 inhibitor, not only effectively attenuated the inhibitory effect of PCDH7 on cell apoptosis induced by ABT-263 in vitro but also sensitized PCDH7-overexpressed CRC cell-derived xenografts to ABT-263 in vivo. Taken together, although PCDH7 inhibited the migration and invasion of CRC cells, it could facilitate the development of drug resistance in colorectal cancer cells by positively modulating Mcl-1 expression. The application of the Mcl-1 inhibitor S63845 could be a potential strategy for CRC chemotherapy, especially in CRC with high levels of PCDH7.

α‑hederin overcomes hypoxia‑mediated drug resistance in colorectal cancer by inhibiting the AKT/Bcl2 pathway.

Currently, chemoresistance is a major challenge that directly affects the prognosis of patients with colorectal cancer (CRC). In addition, hypoxia is associated with poor prognosis and therapeutic resistance in patients with cancer. Accumulating evidence has shown that α‑hederin has significant antitumour effects and that α‑hederin can inhibit hypoxia‑mediated drug resistance in CRC; however, the underlying mechanism remains unclear. In the present study, viability and proliferation assays were used to evaluate the effect of α‑hederin on the drug resistance of CRC cells under hypoxia. Sequencing analysis and apoptosis assays were used to determine the effect of α‑hederin on apoptosis under hypoxia. Western blot analysis and reverse transcription‑quantitative PCR were used to measure apoptosis‑related protein and mRNA expression levels. Furthermore, different mouse models were established to study the effect of α‑hederin on hypoxia‑mediated CRC drug resistance invivo. In the present study, the high expression of Bcl2 in hypoxic CRC cells was revealed to be a key factor in their drug resistance, whereas α‑hederin inhibited the expression of Bcl2 by reducing AKT phosphorylation invitro and invivo, and promoted the apoptosis of CRC cells under hypoxia. By contrast, overexpression of AKT reversed the effect of α‑hederin on CRC cell apoptosis under hypoxia. Taken together, these results suggested that α‑hederin may overcome hypoxia‑mediated drug resistance in CRC by inhibiting the AKT/Bcl2 pathway. In the future, α‑hederin may be used as a novel adjuvant for reversing drug resistance in CRC.

The E3 Ligase TRIM25 Impairs Apoptotic Cell Death in Colon Carcinoma Cells via Destabilization of Caspase-7 mRNA: A Possible Role of hnRNPH1.

Therapy resistance is still a major reason for treatment failure in colorectal cancer (CRC). Previously, we identified the E3 ubiquitin ligase TRIM25 as a novel suppressor of caspase-2 translation which contributes to the apoptosis resistance of CRC cells towards chemotherapeutic drugs. Here, we report the executioner caspase-7 as being a further target of TRIM25. The results from the gain- and loss-of-function approaches and the actinomycin D experiments indicate that TRIM25 attenuates caspase-7 expression mainly through a decrease in mRNA stability. The data from the RNA pulldown assays with immunoprecipitated TRIM25 truncations indicate a direct TRIM25 binding to caspase-7 mRNA, which is mediated by the PRY/SPRY domain, which is also known to be highly relevant for protein-protein interactions. By employing TRIM25 immunoprecipitation, we identified the heterogeneous nuclear ribonucleoprotein H1 (hnRNPH1) as a novel TRIM25 binding protein with a functional impact on caspase-7 mRNA stability. Notably, the interaction of both proteins was highly sensitive to RNase A treatment and again depended on the PRY/SPRY domain, thus indicating an indirect interaction of both proteins which is achieved through a common RNA binding. Ubiquitin affinity chromatography showed that both proteins are targets of ubiquitin modification. Functionally, the ectopic expression of caspase-7 in CRC cells caused an increase in poly ADP-ribose polymerase (PARP) cleavage concomitant with a significant increase in apoptosis. Collectively, the negative regulation of caspase-7 by TRIM25, which is possibly executed by hnRNPH1, implies a novel survival mechanism underlying the chemotherapeutic drug resistance of CRC cells. The targeting of TRIM25 could therefore offer a promising strategy for the reduction in therapy resistance in CRC patients.

Resveratrol Loaded Liposomes Disrupt Cancer Associated Fibroblast Communications within the Tumor Microenvironment to Inhibit Colorectal Cancer Aggressiveness

Colorectal cancer (CRC) is a cancer-associated fibroblast, CAF-rich tumor. CAF promotes cancer cell proliferation, metastasis, drug resistance via secretes soluble factors, and extracellular matrices which leads to dense stroma, a major barrier for drug delivery. Resveratrol (RES) is a polyphenolic compound, has several pharmacologic functions including anti-inflammation and anticancer effects. Considering tumor microenvironment of CRC, resveratrol-loaded liposome (L-RES) was synthesized and employed to inhibit CAF functions. The L-RES was synthesized by thin-film hydration method. The cytotoxicity of L-RES was evaluated using MTT assay. Effect of L-RES treated CAF on tumor spheroid growth was performed. Cell invasion was determined using spheroid invasion assay. The effect of L-RES on 5-fluorouracil (5-FU) sensitivity of CRC cells was determined in co-cultured tumor spheroids. Subtoxic dose of L-RES was selected to study possible inhibiting CAF functions. Decreased CAF markers, α-SMA and IL-6 levels, were observed in L-RES treated activated fibroblast. Interestingly, the activated fibroblast promoted invasive ability and drug resistance of CRC cells in co-culture condition of both 2D and 3D cultures and was attenuated by L-RES treatment in the activated fibroblast. Therefore, L-RES provides a promising drug delivery strategy for CRC treatment by disrupting the crosstalk between CRC cells and CAF.

Potential Biomarkers in Drug-Resistant Colorectal Cancer Cells

Potential Biomarkers in Drug-Resistant Colorectal Cancer Cells

Abstract 6328: GPR56 as a therapeutic target for the development of antibody-drug conjugates for the treatment of colorectal cancer

Abstract Cancer stem cell (CSC) marker LGR5 is highly expressed in colorectal cancer (CRC) and has been considered as a therapeutic target for the treatment of CRC. Previously, we and others showed that CRC tumors were eliminated by treatment with LGR5-targeted antibody-drug conjugates (ADCs). However, a fraction of tumors eventually recurred, likely due to CSC plasticity or the ability of LGR5-positive CSCs to interconvert into more drug resistant LGR5-negative cancer cells. Through our efforts to identify underlying mechanisms of drug resistance and plasticity and develop therapies to eliminate CRC, we showed that GPR56 expression is increased with loss of LGR5 protein expression. GPR56 is a member of the adhesion G-protein coupled receptor (GPCR) family which mediates diverse functions, including cell adhesion and tumorigenesis. GPR56 is also upregulated in CRC and increased expression levels correlate with poor patient survival. We recently showed GPR56 can promote tumor growth and drug resistance of CRC cells through upregulation of multidrug resistance proteins. These findings identify GPR56 as a potential therapeutic target for the treatment of CRC. Presently, we are focused on the development and characterization of anti-GPR56 ADCs that selectively bind GPR56-high CRC cells to deliver potent cytotoxic drugs and destroy them. We reported the generation of unique anti-GPR56 monoclonal antibodies (mAbs) and are currently developing and optimizing GPR56-targeted ADCs conjugated with different drugs. Cell-based binding assays show that our anti-GPR56 mAb binds with high affinity and specificity to 293T cells overexpressing recombinant GPR56 or GPR56-high CRC cells, with no detectable binding to GPR56-negative cells. Using cytotoxicity assays, we evaluated the in vitro efficacy of anti-GPR56 ADCs against several CRC lines with different levels of GPR56 expression and showed that the ADC is only effective against CRC cells expressing GPR56. Moreover, we evaluated the therapeutic efficacy of our anti-GPR56-ADC against CRC cell line and patient-derived tumor xenograft models in vivo and demonstrated significant inhibition of tumor growth. Altogether, these findings suggest that novel GPR56-targeted ADCs may be a promising therapeutic strategy to overcome resistance for the improved treatment of CRC. Citation Format: Liezl E. Francisco, Treena Chatterjee, Zhengdong Liang, Sheng Zhang, Kendra Carmon. GPR56 as a therapeutic target for the development of antibody-drug conjugates for the treatment of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6328.

Cullin-9/p53 mediates HNRNPC degradation to inhibit erastin-induced ferroptosis and is blocked by MDM2 inhibition in colorectal cancer.

Colorectal cancer (CRC) is the leading cause of cancer associated death worldwide. Ferroptosis is a newly defined form of regulated cell death characterized by the accumulation of lipid hydroperoxides and exerts an increased attention for cancer treatment. However, little is known about ferroptosis in CRC. In this study, through whole genome sequencing and external differential differentiated expression analysis, we identify CUL9 as a novel important modulator for ferroptosis in CRC. Here we demonstrated that CUL9 can binds p53 to ubiquitylate heterogeneous nuclear ribonucleoprotein C for degradation. Overexpression of CUL9 increases resistance to erastin-induced ferroptosis. Then, we discovered this resistance was mediated by CUL9-HNRNPC-MATE1 negative loop, which can provide us with a novel target to overcome drug resistance to ferroptosis activators. Finally, we found that targeting MDM2 was developed as an effective strategy to destroy precious drug-resistant CRC cells.

Downregulation of miRNA-14669 Reverses Vincristine Resistance in Colorectal Cancer Cells through PI3K/AKT Signaling Pathway

Vincristine (VCR) is a chemotherapeutic drug commonly used in the treatment of Colorectal Cancer (CRC). However, VCR drug resistance may result in reduced efficacy and even failure of chemotherapy in CRC treatment. MiRNA has been demonstrated to be associated with the sensitivity of tumor cells to chemotherapy. This study aimed to identify a novel miRNA-14669 that can reverse vincristine resistance and sensitize drug-resistant colorectal cancer cells. High-throughput sequencing was performed to screen miRNAs that are associated with VCR drug resistance, and qRT-PCR was used for further validation. The miRNA mimic and inhibitor were designed and transfected into HCT-8,HCT-116 and HCT-8/VCR cells. Wound healing test examined the effect of the miRNA on the migration of colorectal cancer cells. Flow cytometry was used to evaluate cell apoptosis of HCT-8 cells. Survivin, Bcl-2, GST3, MDR1 and MRP1 expressions were detected by Western blot. The expression of miRNA-14669 in HCT-8/VCR cells was 1.925 times higher than that of the HCT-8 cells. After transfecting with mimic miRNA, HCT-8 and HCT-116 cells showed an increased survival rate. The survival rate of HCT-8/VCR cells decreased by transfection of inhibitor. The inhibitor also sensitized HCT-8 and HCT-116 cells to VCR or 5-Fluorouracil (5-FU). The migratory ability of HCT-8 and HCT-116 cells increased by miRNA mimic while reduced by miRNA inhibitor. Overexpression of miRNA-14669 reduced apoptosis, while downregulation of miRNA- 14669 increased cell apoptosis in HCT-8 cells. The mechanism of the miRNA involved in drug resistance may be attributed to apoptosis of tumor cells, detoxification of GST3 and drug efflux induced by MDR1 and MRP1. PI3K / AKT is the signaling pathway related to drug resistance. We identified a novel miRNA-14669 that may be associated with the chemotherapeutic resistance in CRC cells.

Kaempferol Can Reverse the 5-Fu Resistance of Colorectal Cancer Cells by Inhibiting PKM2-Mediated Glycolysis.

Resistance to 5-Fluorouracil (5-Fu) chemotherapy is the main cause of treatment failure in the cure of colon cancer. Therefore, there is an urgent need to explore a safe and effective multidrug resistance reversal agent for colorectal cancer, which would be of great significance for improving clinical efficacy. The dietary flavonoid kaempferol plays a key role in the progression of colorectal cancer and 5-Fu resistance. However, the molecular mechanism of kaempferol in reversing 5-Fu resistance in human colorectal cancer cells is still unclear. We found that kaempferol could reverse the drug resistance of HCT8-R cells to 5-Fu, suggesting that kaempferol alone or in combination with 5-Fu has the potential to treat colorectal cancer. It is well known that aerobic glycolysis is related to tumor growth and chemotherapy resistance. Indeed, kaempferol treatment significantly reduced glucose uptake and lactic acid production in drug-resistant colorectal cancer cells. In terms of mechanism, kaempferol promotes the expression of microRNA-326 (miR-326) in colon cancer cells, and miR-326 could inhibit the process of glycolysis by directly targeting pyruvate kinase M2 isoform (PKM2) 3′-UTR (untranslated region) to inhibit the expression of PKM2 or indirectly block the alternative splicing factors of PKM mRNA, and then reverse the resistance of colorectal cancer cells to 5-Fu. Taken together, our data suggest that kaempferol may play an important role in overcoming resistance to 5-Fu therapy by regulating the miR-326-hnRNPA1/A2/PTBP1-PKM2 axis.

LRP5 promotes cancer stem cell traits and chemoresistance in colorectal cancer.

The overactivation of canonical Wnt/β‐catenin pathway and the maintenance of cancer stem cells (CSCs) are essential for the onset and malignant progression of most human cancers. However, their regulatory mechanism in colorectal cancer (CRC) has not yet been well demonstrated. Low‐density lipoprotein receptor‐related protein 5 (LRP5) has been identified as an indispensable co‐receptor with frizzled family members for the canonical Wnt/β‐catenin signal transduction. Herein, we show that activation of LRP5 gene promotes CSCs‐like phenotypes, including tumorigenicity and drug resistance in CRC cells, through activating the canonical Wnt/β‐catenin and IL‐6/STAT3 signalling pathways. Clinically, the expression of LRP5 is upregulated in human CRC tissues and closely associated with clinical stages of patients with CRC. Further analysis showed silencing of endogenous LRP5 gene is sufficient to suppress the CSCs‐like phenotypes of CRC through inhibiting these two pathways. In conclusion, our findings not only reveal a regulatory cross‐talk between canonical Wnt/β‐catenin signalling pathway, IL‐6/STAT3 signalling pathway and CD133‐related stemness that promote the malignant behaviour of CRC, but also provide a valuable target for the diagnosis and treatment of CRC.

LIM-Domain-Binding Protein 1 Mediates Cell Proliferation and Drug Resistance in Colorectal Cancer.

Objective: It has been shown that LIM-domain-binding protein 1 (LDB1) is involved in the tumorigenesis of several cancers, but its function in colorectal cancer (CRC) has not been fully explained. This study is aimed to investigate whether LDB1 is involved in regulating the cell growth and drug sensitivity of CRC.Methods: To analyze the protein expression of LDB1 in CRC tissues, western blot was used. KM plotter and UALCAN databases were used to predict the prognosis of CRC patients with low or high LDB1 expression. To do the correlation analysis in CRC tissues, GEPIA database was used. CCK-8 assay and xenograft models were used to evaluate the effects of LDB1 in CRC cell growth. An oxaliplatin-resistant cell line was constructed to evaluate the effect of LDB1 in drug sensitivity of CRC cells.Results: Our current research confirmed that LDB1 was upregulated in CRC tumor tissues, and its elevation predicted a poor prognosis for CRC patients. LDB1 was also found positively correlated with CCNA1, BCL2 and BCLW, but negatively correlated with the pro-apoptotic signals (BID, BAX and BAK). Silence of LDB1 significantly inhibited CRC cell growth in vitro, and CRC cells with low expression of LDB1 had a lower tumorigenesis rate in tumor-bearing nude mice. Our experiments also showed that LDB1 silence enhanced the anti-tumor activity of oxaliplatin in CRC cells. The expression of LDB1 was also found increased in oxaliplatin-resistant CRC cell lines, and silence of LDB1 partly restored the antitumor effect of oxaliplatin in an oxaliplatin-resistant CRC cell line.Conclusion: Our current results revealed the roles of LDB1 in the growth and drug resistance of CRC cells, and may provide the new theoretical support for LDB1 as a potential target for the treatment of CRC in the future.

SOX4 induces drug resistance of colorectal cancer cells by downregulating CYLD through transcriptional activation of microRNA-17.

Exposure to high doses of anticancer drugs can induce the emergence of a subpopulation of weakly proliferative and drug-tolerant cells. Drug tolerance can reduce the benefits obtained from canonical treatment and reduce the survival rate of patients. Regulation of SRY-related HMG box transcription factor 4 (SOX4) has been proved to affect drug sensitivity. The current study aimed to explore the role of SOX4 in drug resistance of colorectal cancer (CRC) cells as well as the related molecular mechanisms. Expression patterns of SOX4, microRNA-17 (miR-17), and CYLD in both CRC tissues and cells were determined with their relationship analyzed by bioinformatics analysis, dual-luciferase reporter gene assay, and ChIP. Loss- and gain-function assays were performed to ascertain the effect of SOX4, miR-17, and CYLD on biological cellular processes and drug resistance to 5-FU. SOX4 and miR-17 were found to be highly expressed while CYLD was poorly expressed in CRC tissues and cells. Silencing of SOX4 resulted in the suppression of cellular proliferation, invasion, migration as well as a reduction in CRC drug resistance. Mechanically, CYLD was specifically targeted by miR-17, while SOX4 upregulated the expression of miR-17. Functionally, SOX4 triggered drug resistance of CRC cells to 5-FU through the miR-17/CYLD axis. Taken together, the key findings of the present study provides evidence suggesting that SOX4 elevates miR-17 to decrease CYLD, thus inducing chemotherapy resistance of CRC cells.

ECHS1, an interacting protein of LASP1, induces sphingolipid-metabolism imbalance to promote colorectal cancer progression by regulating ceramide glycosylation

Sphingolipid metabolic dysregulation has increasingly been considered to be a drug-resistance mechanism for a variety of tumors. In this study, through an LC–MS assay, LIM and SH3 protein 1 (LASP1) was identified as a sphingolipid-metabolism-involved protein, and short-chain enoyl-CoA hydratase (ECHS1) was identified as a new LASP1-interacting protein through a protein assay in colorectal cancer (CRC). Gain- and loss-of-function analyses demonstrated the stimulatory role played by ECHS1 in CRC cell proliferation, migration, and invasion in vitro and in vivo. Mechanistic studies of the underlying tumor-supportive oncometabolism indicate that ECHS1 enables altering ceramide (Cer) metabolism that increases glycosphingolipid synthesis (HexCer) by promoting UDP-glucose ceramide glycosyltransferase (UGCG). Further analysis showed that ECHS1 promotes CRC progression and drug resistance by releasing reactive oxygen species (ROS) and interfering mitochondrial membrane potential via the PI3K/Akt/mTOR-dependent signaling pathway. Meanwhile, the phenomenon of promoting the survival and drug resistance of CRC cells caused by ECHS1 could be reversed by Eliglustat, a specific inhibitor of UCCG, in vitro and in vivo. IHC assay showed that ECHS1 was overexpressed in CRC tissues, which was related to the differentiation and poor prognosis of CRC patients. This study provides new insight into the mechanism by which phospholipids promote drug resistance in CRC and identifies potential targets for future therapies.